Errors

When an error occurs, DrScheme highlights the source of the error, whether it is in the definitions window or the interactions window. For example, typing (/ 1 0) in the interactions window causes that expression to be highlighted (and also produces the error message ``/: division by zero'').

Exercise Notes

Exercise 2.4.1 If DrScheme gives the error message ``procedure application: expected procedure'' for the expression (+ (10) 20) make sure that the language level is set to Beginning Student, as described in Preparing DrScheme. The correct error message is more specific: ``First term after parenthesis is illegal in an application''.